By default the JavaFX formatter seems to format this code:
    action: function() {

into this:

    action: function () {

In other words it adds a space between "function" and "()" for anonymous functions.

That's a bit unusual (and I don't see ANY occurrences of that formatting anywhere in the SDK source code).

Note that I looked at the JavaFX formatting options, and the option for adding a space before the function call parentheses was false.

I'm guessing the formatter is simply inserting the space that usually separates the function keyword and the function name, without checking whether there is a function name to be separated from the keyword.